Fuse



P. M. KELLEY ET Al.

FUSE

Filed July 19 1930 I I Sv INVENTORS Au n. u ./Av-sl.. cfg fg 6; ATTORNEYS Sept. 29, 1931.

Patented Sept. 29, 1931 UNITED STATES PATENT OFFICE PAUL M.-KEL`LEY, OF NEW YORK, N. Y., AND JAMES L. CLAYTON; OF

NEW JERSEY FUSE Application led July 19,

This invention relates to improvements in electrical fuses and has particular reference to a fuse of the type employed in so-called cross connection boXes which form part of the telephone equipment used in connecting aerial and underground cables.

In the type of cross connection boxes employed in the past by telephone companies, the fuses are each mounted at only one end thereof upon a terminal memberA secured in a panelof the box.. This terminal member comprises a hollow shank externally and in ternally screw threaded, the former threads being utilized to receive a backing nut which engages the inner face of the panel to hold the member in' position, while the internal threads receive an externally threaded eX- tension at one end of a fuse. Experience has shown that,fduer to various reasons, among which is the thinness of the material of the Shanks of the terminal members and the rusting of said material, said Shanks often break oil', thereby disrupting an electrical connection. This breaking' usually occurs at a point contiguous to the backing nut andit then becomes necessary to replace the broken'oif fuse. This may be done either by using the same type of fuse with the threaded eXtension, which is then inserted int-o the remaining portion of the shank of the terminal member, or there may be employed a diiferent type of ifuse which is nowgenerally being subsituted for the first-named kind. lVhether the new or old type is used for 1eplacementk depends somewhat upon 'the nature ot the break occurring in the shank of the terminal member.- If the break is such that there are not suilicient internal threads of the shank remaining with which to engage the threaded extension of the old type of fuse, thenit is necessary to remove from the shank, by means of a special tool, the backing nut referred to above and then thread the new type of fuse on to the external threads of the remaining portion of said shank which have been uncovered by the removal of said nut. The new type of fuse has an internal thread to receive said shank as distinguished from the externally threaded extension of the old type. In either case of replacement, it is COYTESVILLE,

1930. Serial No. 469,222.

necessary for the repairman to carry both types of fuses.

vThere is also being used at present a neuT kind of connection box in which the terminal members' vthereof are provided with solid threaded shanks instead of thehollow ones and the internal threads of the new type of fuses above mentioned are adapted to fit those of said solid shanks. These new yterminal members may be also substituted for the old kind, wherever it is found expedient to do so, by removing the aforesaid backing nut and then withdrawing the old member from the outer side of the panel in which it is mounted, whereupon the new terminal member can be inserted into the opening in said panel.

In accordance with the present invention, it is proposed to provide ran improved fuse which is universally adaptable to either type of terminal member, thereby elfecting a saving in expensive equipment and eliminating the necessity of the repairman carrying two different types of fuses.

The inventive idea involved is capable of receiving a variety of mechanical expressions, one of which, for purposes of illustration, is shown in the accompanying drawings, wherein:

Figure 1 is a side elevatiompartly in longitudinal section, of a fuse constructed in ac# cordance with the present invention;

Figure 2 is a sectional view illustrating the adaptation of ther fuse to a new type'of terminal member;

Figure 3 is a similar view showing the fuse connected to the old type` of terminal member and e.

Figure 4 is an end elevation of the fuse.

Referring more particularly to the drawings, there is shown therein only so much of a cross connection box as is necessary to a com# plete understanding of the invention. The back panl of a box is indicated in Figures 2 and 3 by the numeral 5 and in this panel are provided a plurality of openings (teach adapted to receivea,terminal member. In Figure 3, the terminal member Tis shown to be of the type used in old connection boxes and comprises a shank 8 which, for at least a portion of its length, is of hollow construction and is provided with external and internal threads 9 and 10. The shank 8 is insertable into the opening 6 and the threads 9 are employed to receive thereon the backing nut 11 Which engages the inner face of the panel to retain the member 7 in position. The threads 10 are adapted to be engaged by the externally threaded extension of an old type ot fuse to support the latter in position. It is with this construction that dilliculty has been experienced, the shanks 8 very often breaking olf adjacent the nut 11 and sometimes in such manner that an insufficient number of the internal threads of the shank are let't to receive and properly hold the extension of the old type of fuse. Then this occurs,

and it is desired to mount another fuse in the position formerly occupied by the broken-oill fuse, the rep airman must tirst remove the nut 11 by means of a special tool and then Withdraw the terminal member 7 from its opening in the panel 5. Then this is done, a new type of terminal member 12 (Figure 2), which new being employed in equipment of this character, is inserted into the openingr 6. In contradistinction to the hollow construction of the shank of the old type of terminal niember, the member 12 is provided With a solid externally threaded shank 13. After its insertion into the opening G, the backingl nut 1l is threaded upon the shank 13 and engaged with the panel 5 to secure said terminal in position. The terminal member is then ready to receive the type of fuse which is noiv generally used and which is provided at one end with an internally threaded socket of uniform diameter. It is apparent from the foregoing that it is necessary for the repairman to carry both kinds of fuses owing to the tact that the old fuse will not it the new terminal member and vice versa.

The present invention further proposes the use of an entirely new fuse which can be universally adapted to both types of terminal members employed in the connection boxes. To this end, the new fuse comprises a tubular body 14 made of insulation material and having mounted in one end thereof a terminal post 15 to which a cable may be secured by means of the Init 16 and Washer 17. Extending from the terminal post 15 through the opening 18 in the body is the usual fuse element 19. At the end of the body opposite the post 15 there is secured in the opening 18, by means of a transverse pin 20, a tubular coupling member 21 to Which the adjacent end of the fuse element 19 is connected and which is utilized to oin the fuse to either (if the terminal members 7 or 12, said member being entirely countersunk Within the insulation body 14. For connecting the fuse to the termi nal member 12, the inner or major portion of the lengt-h of the coupling member 21 is provided with the internal threads 22 which are adapted to receive the shank 13 of said member, as shown in Figure 2. To make the member 21 adaptable to the old type of terminal member 7, the outer end of said lnember is provided with an enlargement 23, the opening in Which is screw threaded and is of a diameter equal to the exterior diameter of the shank 8 ofthe member 7. When mounting the fuse upon the member 7, the threads of the enlargement 23 are engaged with the external threads 9 of the shank and the extremity of the fuse engaged with the backing nut. However, if the fuse is to be mounted upon a broken shank 8, the backing nut 11 is removed, thereby exposing some of the threads 9 of the remaining portion of the terminal member and the fuse is then engaged with said threads and turned until the extremity of the fuse contacts with the panel 5 to support the fuse and terminal member in position.

lVhat is claimed is:

1. A fuse comprising a body, a fuse element therein, and a coupling member at one end of said body to which said fuse element is con nected and having internal screw threads of dillerent diameters capable of receiving different sized Shanks of terminal members.

2. A fuse comprising a body, a fuse element therein, and a tubular coupling member mounted Within one end of said bod and having an enlargement at its outer en( the interior of said member and the enlargel'nent thereof being screw threaded to receive diterent sized shanks of terminal members.

3. A fuse comprising an insulated body, a fuse element in said body and a tubular coupling member countersunk within one end ot' said body and having an inner internally threaded portion andan outer internally threaded portion of larger' diameter than said inner portion.

4. A fuse adapted for universal connection to different types of terminal members Vin cross connection boxes, said fuse comprising a tubular body of insulated material, the opening of which is enlarged at one end, a terminal post at the other end of said body, a coupling member mounted in the firstnamed end, and a fuse element connecting said terminal post and coupling member, the latter having its entire length encased within said body and provided with an enlarged portion fitting within the enlargement uof said body, and also having internal threads of different diameters to receive correspondingly sized Shanks of terminal members.

In testimony whereof we have aflixed our signatures.

PAUL M. KELLEY. JAMES L. CLAYTON ICO 

